The cycle is well established at this point. Hollywood makes a movie about something you loved as a child, and then you whine about it. That's what happened with Transformers and Alvin and the Chipmunks and Yogi Bear and countless other childhood-destroying monstrosities. But it seems a bit redundant to whine about Hollywood ruining the Teenage Mutant Ninja Turtles, because the turtles already did that to themselves, years ago.

Look back at it if you need proof. The original cartoons are almost unwatchably jerky. The film series quickly descended into time-travel plots and CGI irrelevancies and Vanilla Ice cameos. The thought of anyone – least of all a six-foot kung-fu tortoise – saying the word "cowabunga" out loud in 2012 is sphincter-obliteratingly awful. There's not much point in banging on about Hollywood spoiling it, because it was never really that much cop in the first place.

And yet Hollywood, God bless it, is doing its best. A few days ago, a 15-second video emerged online. It shows producer Michael Bay standing before an audience in a suit, discussing his plans for a new Teenage Mutant Ninja Turtles film, to be directed by Jonathan Liebesman of Wrath of the Titans fame, with such a dearth of enthusiasm that you could quite easily mistake him for a printer toner spokesman at a regional office supplies conference.

In the video, Bay says: "Kids are going to believe one day that these turtles actually do exist when we are done with this movie. These turtles are from an alien race and they are going to be tough, edgy, funny and completely lovable."

Now, hang on a minute. From an alien race? That's not how it works. That's not how it works at all. Everyone knows that the turtles came about because they were exposed to radioactive material as babies. They're mutants. They're quite definitively not aliens. They're called the Teenage Mutant Ninja Turtles, not the Teenage Alien Race of Turtle-like Creatures Who Happen to Know Ninja.

Making the turtles aliens would ruin everything – their desire to be accepted, their bizarre late-1980s street lingo, their fondness for pizza. Everything. Are we really meant to believe that there's an alien race of giant turtles who just happen to all be named after renowned Renaissance artists from this planet, and speak English, and who came to Earth with a giant elderly rat who's presumably from the same race, just to live in sewers and loudly eschew anchovies at every opportunity? Hardly, Michael Bay. Hardly.

At least Bay has been sensible enough to alter the film's title as a consequence of this decision. Due out next Christmas, it'll simply be entitled Ninja Turtles. No mention of mutants anywhere. But similarly no mention of teenagers. Maybe the turtles won't be teenagers, either. Maybe they'll be middle-aged, and they'll fill every moment of downtime discussing traffic and the weather and how young people don't listen to real music any more. It sounds ridiculous, but no less ridiculous than making them aliens.

So there we have it. The vast array of witless, money-grabbing cash-in jobs that have emerged over the last 20 years have ensured that expectations of any new Teenage Mutant Ninja Turtles movie couldn't possibly be any lower. And yet, thanks to a combination of Bay, Liebesman and a deliberately misunderstood origins story, it looks like we might all end up being disappointed anyway. That takes some doing.